Non-volatile memory device and operating method thereof for performing an erase detect operation

ABSTRACT

An operating method of a non-volatile memory device including a plurality of memory cells respectively connected to a plurality of word lines is provided. The operating method includes applying an erase detect voltage to a selected word line of the plurality of word lines to perform an erase detect operation on memory cells connected to the selected word line in response to a program command, applying a program voltage to the selected word line after the erase detect operation, and counting a number of undererased cells of the memory cells on which the erase detect operation has been performed.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Korean Patent Application No.10-2017-0132754, filed on Oct. 12, 2017, in the Korean IntellectualProperty Office, the disclosure of which is incorporated herein in itsentirety by reference.

BACKGROUND

Inventive concepts relate to a memory device, and more particularly, toa non-volatile memory device and an operating method thereof, whichdetect and repair a defective word line.

Memory devices may be used to store data and may be categorized intonon-volatile memory devices and volatile memory devices. As an exampleof non-volatile memory devices, flash memory devices may be applied toportable phones, digital cameras, personal digital assistants (PDAs),mobile computer devices, fixed computer devices, and/or other devices.Recently, as information communication devices are being equipped withmultiple functions, large-capacity and highly integrated memory devicesare desired.

SUMMARY

Inventive concepts provide a non-volatile memory device and an operatingmethod thereof.

According to some example embodiments of inventive concepts, there isprovided an operating method of a non-volatile memory device including aplurality of memory cells respectively connected to a plurality of wordlines, the operating method including applying an erase detect voltageto a selected word line of the plurality of word lines to perform anerase detect operation on memory cells connected to the selected wordline in response to a program command, applying a program voltage to theselected word line after the erase detect operation, and counting anumber of undererased cells of the memory cells on which the erasedetect operation has been performed.

According to some example embodiments of inventive concepts, there isprovided an operating method of a non-volatile memory device including aplurality of memory cells respectively connected to a plurality of wordlines, the operating method including applying a program voltage to aselected word line of the plurality of word lines in response to aprogram command, applying an erase detect voltage to the selected wordline to perform an erase detect operation on program-inhibited memorycells of memory cells connected to the selected word line after theapplying of the program voltage, and counting a number of undererasedcells of the program-inhibited memory cells on which the erase detectoperation has been performed.

According to some example embodiments of inventive concepts, there isprovided an operating method of a non-volatile memory device including aplurality of memory cells respectively connected to a plurality of wordlines, the operating method including applying a program voltage to aselected word line of the plurality of word lines in response to aprogram command, performing a program verify operation on programmedmemory cells of memory cells connected to the selected word line byusing a program verify voltage, performing an erase detect operation onprogram-inhibited memory cells of the memory cells connected to theselected word line by using the program verify voltage, and counting anumber of undererased cells of the program-inhibited memory cells onwhich the erase detect operation has been performed.

According to some example embodiments of inventive concepts, there isprovided a non-volatile memory device including a memory cell arrayincluding a plurality of memory cells respectively connected to aplurality of word lines, a page buffer unit including a plurality ofpage buffers respectively connected to memory cells connected to aselected word line of the plurality of word lines and configured torespectively store erase detect results of the memory cells before or inthe middle of performing a program operation on the selected word line,and a counter connected to the plurality of page buffers and configuredto count a number of undererased cells from the erase detect results.

BRIEF DESCRIPTION OF THE DRAWINGS

Example embodiments of inventive concepts will be more clearlyunderstood from the following detailed description taken in conjunctionwith the accompanying drawings in which:

FIG. 1 is a block diagram illustrating a memory system according to anembodiment;

FIGS. 2A and 2B illustrate examples of an operation of a memory deviceincluding a defective word line;

FIG. 3 is a block diagram illustrating a memory device according to anembodiment;

FIG. 4 illustrates an equivalent circuit diagram of a first memory blockof FIG. 3;

FIG. 5 is a perspective view illustrating the first memory block of FIG.3;

FIG. 6A illustrates a threshold voltage distribution of memory cells ofFIG. 4;

FIG. 6B illustrates a program method of forming the threshold voltagedistribution of FIG. 6A;

FIG. 7 is a flowchart illustrating an operating method of a memorydevice according to an embodiment;

FIG. 8 illustrates a threshold voltage distribution of memory cellsbased on the operating method of FIG. 7;

FIG. 9 is a flowchart illustrating a program method of a memory deviceaccording to an embodiment;

FIGS. 10A and 10B are timing diagrams showing the program method of FIG.9;

FIGS. 11A to 11C illustrate program sequences for performing a programmethod according to an embodiment;

FIGS. 12 and 13 are flowcharts illustrating an operation between amemory controller and a memory device, according to some exampleembodiments;

FIG. 14 illustrates a memory device according to an embodiment;

FIG. 15 is a flowchart illustrating an operating method of a memorydevice according to an embodiment;

FIG. 16 illustrates a threshold voltage distribution of memory cellsbased on the operating method of FIG. 15;

FIG. 17 is a flowchart illustrating a program method of a memory deviceaccording to an embodiment;

FIGS. 18A and 18B are timing diagrams showing the program method of FIG.17;

FIG. 19 is a flowchart illustrating an operating method of a memorydevice according to an embodiment;

FIG. 20A is a circuit diagram illustrating a page buffer according to anembodiment;

FIG. 20B is a timing diagram showing control signals applied to the pagebuffer of FIG. 20A;

FIG. 21 illustrates a threshold voltage distribution of memory cellsbased on the operating method of FIG. 19;

FIG. 22 illustrates a memory device according to an embodiment;

FIG. 23 is a flowchart illustrating a program method of a memory deviceaccording to an embodiment;

FIG. 24 is a timing diagram for describing an example of an operation ofa page buffer unit of FIG. 22, based on the program method of FIG. 23;

FIGS. 25A and 25B are timing diagrams showing the program method of FIG.23;

FIG. 26 is a timing diagram for describing an example of an operation ofthe page buffer unit of FIG. 22, based on the program method of FIG. 23;

FIG. 27 is a flowchart illustrating an operating method of a memorydevice according to an embodiment; and

FIG. 28 is a block diagram illustrating an example where a memory deviceaccording to embodiments is applied to a solid state drive (SSD) system.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

The various operations of methods described above may be performed byany suitable means capable of performing the operations, such as varioushardware, circuits, and/or module(s). The blocks or steps of a method oralgorithm and functions described in connection with the embodimentsdisclosed herein may be embodied directly in hardware.

Hereinafter, embodiments will be described in detail with reference tothe accompanying drawings.

FIG. 1 is a block diagram illustrating a memory system 10 according toan embodiment.

Referring to FIG. 1, the memory system 10 may include a memory device100 and a memory controller 200. The memory device 100 may be, or mayinclude, a non-volatile memory device and may be implemented as a memorychip. The memory device 100 may include a memory cell array 110, a pagebuffer unit 120, and a counter 130. In some example embodiments, thememory system 10 may be implemented with an internal memory embeddedinto an electronic device, and for example, may be, or may include, anembedded universal flash storage (UFS) memory device, embeddedmulti-media card (eMMC), or solid state drive (SSD). In some exampleembodiments, the memory system 10 may be implemented with an externalmemory attachable/detachable on/from an electronic device, and forexample, a UFS memory card, compact flash (CF), secure digital (SD),micro secure digital (Micro-SD), mini secure digital (Mini-SD), extremedigital (xD), or memory stick.

In response to a read/write request from a host HOST, the memorycontroller 200 may control the memory device 100 to read data stored inthe memory device 100 or program data in the memory device 100. Indetail, the memory controller 200 may provide a command CMD, an addressADDR, and a control signal CTRL to the memory device 100 to control aprogram operation, a read operation, and an erase operation on thememory device 100. Also, data DATA to program and read data DATA may betransmitted or received between the memory controller 200 and the memorydevice 100. The memory controller 200 may include an error correctingcode (ECC) engine 210, and the ECC engine 210 may correct an error indata received from the memory device 100.

The memory cell array 110 may include a plurality of memory cells, andfor example, the plurality of memory cells may be flash memory cells.Hereinafter, an example where the plurality of memory cells are flashmemory cells will be described. However, the embodiment is not limitedthereto. In other embodiments, the plurality of memory cells may beresistive memory cells such as resistive random access memory (ReRAM),phase change random access memory (PRAM), or magnetic random accessmemory (MRAM). In some example embodiments, the memory cell array 110may include a two-dimensional (2D) memory cell array. In some exampleembodiments, the memory cell array 110 may include a three-dimensional(3D) memory cell array including a plurality of NAND strings, asdescribed below with reference to FIGS. 4 and 5.

The 3D memory cell array may be or may include a circuit that includesan active area disposed on a silicon substrate and is associated with anoperation of each of memory cells, and may be configured in a monolithictype on a physical level of at least one of memory cell arrays eachincluding a circuit which is provided on or in the substrate. Themonolithic type may denote that layers of levels configuring an arrayare stacked just on layers of lower levels of the array. In anembodiment, the 3D memory cell array may include a plurality of NANDstrings which are arranged in a vertical direction in order for at leastone memory cell to be disposed on another memory cell. The at least onememory cell may include a charge trap layer. U.S. Pat. Nos. 7,679,133,8,553,466, 8,654,587 and 8,559,235 and U.S. Patent Application No.2011/0233648 disclose appropriate elements of a 3D memory cell arraywhich include a plurality of levels and in which word lines and/or bitlines are shared between the plurality of levels. In the specification,the above reference documents are incorporated herein by reference intheir entirety.

The page buffer unit 120 may store an erase detect result of each ofmemory cells and may output page buffer signals based on the storederase detect result. In an embodiment, the erase detect result maycorrespond to a voltage of each of sensing nodes respectively connectedto bit lines when an erase detect voltage is applied to a selected wordline, in a program operation. In an embodiment, the erase detect voltagemay be lower than a verify voltage (for example, Vvfy1 of FIG. 6A)having a lowest program state for memory cells. In an embodiment, theerase detect voltage may be the same as the verify voltage having thelowest program state for the memory cells, and a develop time of sensingnodes connected to memory cells on which erase detect is to be performedmay be shorter than a develop time of sensing nodes connected toprogrammed memory cells.

The counter 130 may receive the page buffer signals from the page bufferunit 120, and may count the number of off, or undererased, cells, basedon the received page buffer signals. In this case, a threshold voltageof each of the undererased cells may be greater than the erase detectvoltage. In an embodiment, the undererased cells may correspond tomemory cells on which an erase operation is not normally performed. Anundererased cell may be a cell that, after an erase operation applied tothe cell, still has a threshold voltage greater than the erase detectvoltage. In an embodiment, the undererased cells may correspond tomemory cells where the erase operation has been normally performed but athreshold voltage has increased due to program disturbance.

If the counted number of the undererased cells is greater than areference bit count, a selected word line may be determined as adefective word line. At this time, the memory device 100 may end aprogram operation on memory cells connected to the defective word lineand may process the memory cells connected to the defective word line asa fail block. In an embodiment, the memory device 100 may provide a failmessage to the memory controller 200. In an embodiment, the memorydevice 100 may provide a comparison result, obtained by comparing thecounted number of the undererased cells with the reference bit count, tothe memory controller 200. If the counted number of the undererasedcells is less than or equal to the reference bit count, the memorydevice 100 may not determine the selected word line as the defectiveword line. At this time, the memory device 100 may continuously performthe program operation on memory cells connected to the selected wordline.

FIG. 2A illustrates an example of an operation of a memory deviceincluding a defective word line. Referring to FIG. 2A, an eraseoperation may be performed on the memory device, and then, by applyingan erase verify voltage ERS_VFY to word lines WL, an erase verifyoperation may be performed. A defective word line WLa of the word linesWL may occur due to deterioration of the memory device and/or a processerror caused by an increase in program/erase cycle. At this time, theerase operation may not be normally performed on memory cells connectedto the defective word line WLa, and a threshold voltage of each of thememory cells connected to the defective word line WLa may not besufficiently lowered to the erase verify voltage ERS_VFY or less.

If an erase verify operation is performed on the word lines WL, aprecise erase verify result is obtained, but as the number of the wordlines WL increases, the number of erase verifications increases, whichmay cause an excessive increase in time taken in the erase verifyoperation. Therefore, by simultaneously applying the erase verifyvoltage ERS_VFY to the word lines WL, the erase verify operation may besimultaneously performed on the word lines WL, or the word lines WL maybe divided into two or more groups, and the erase verify operation maybe performed on each of two or more groups. In this case, a time takenin the erase verify operation is reduced, but an accuracy of an eraseverify result may be reduced. For example, the memory cells connected tothe defective word line WLa are not normally erased, but may berecognized as an erase pass according to the erase verify result.

In a case where a program operation is performed on the memory cellsconnected to the defective word line WLa after the erase pass, memorycells which are not normally erased may be programmed to first toseventh program states P1 to P7, and a program operation may be passedaccording to a program verify result. For example, cells in the programstate P5 may have a threshold voltage greater than RD5. In a case wherea read operation is performed on the memory cells connected to thedefective word line WLa after the program pass, a read error may occurdue to an abnormal threshold voltage distribution of memory cells wherea target state is an erase state E. For example, cells in the erasedstate E may overlap with cells in the program state P1, and a voltage ofRD1 may not distinguish cells in the erased state E over cells in theprogram state P1. In detail, an uncorrectable read error (i.e., anuncorrectable ECC) may occur due to an ECC engine (for example, 210 ofFIG. 1) included in a memory controller (for example, 200 of FIG. 1).

FIG. 2B illustrates an example of an operation of a memory deviceincluding a defective word line. Referring to FIG. 2B, based on a resultof an erase operation on the memory device, threshold voltages of memorycells connected to a word line WLb of a plurality of word lines WL maybe very close to an erase verify voltage ERS_VFY. However, the thresholdvoltages of the memory cells connected to the word line WLb may be lowerthan the erase verify voltage ERS_VFY, and thus, an erase pass may beperformed according to the result of the erase operation on the memorydevice. In a case where a program operation is performed on memory cellsconnected to word lines adjacent to the word line WLb after the erasepass, threshold voltages of some of the memory cells connected to theword line WLb may increase to the erase verify voltage ERS_VFY or higherdue to program disturbance. In this manner, a progressive defect where athreshold voltage increases due to program disturbance may occur inmemory cells on which the erase operation has been normally performed.

When the progressive defect occurs, as described above with reference toFIG. 2A, the memory cells connected to the word line WLb may beprogrammed to first to seventh program states P1 to P7, and a programoperation may be passed according to a program verify result. Forexample, cells in the erased state E may overlap with cells in theprogram state P1, and a voltage of RD1 may not distinguish cells in theerased state E over cells in the program state P1. In a case where aread operation is performed on the memory cells connected to the wordline WLb after the program pass, a read error may occur due to anabnormal threshold voltage distribution of memory cells where a targetstate is an erase state E.

FIG. 3 is a block diagram illustrating a memory device 100 according toan embodiment. Referring to FIG. 3, the memory device 100 may include amemory cell array 110, a page buffer unit 120, a counter 130, apass/fail (P/F) checking unit 140, a control logic 150, a voltagegenerator 160, and/or a row decoder 170. Although not shown, the memorydevice 100 may further include a data input/output (I/O) circuit or anI/O interface.

The memory cell array 110 may be connected to the page buffer unit 120through bit lines BL and may be connected to the row decoder 170 throughword lines WL, string selection lines SSL, and ground selection linesGSL. The memory cell array 110 may include a plurality of memory blocksBLK1 to BLKz, and each of the memory blocks BLK1 to BLKz may include aplurality of memory cells. Each of the memory cells may store one ormore bits, and in detail, each of the memory cells may be used as asingle level cell (SLC), a multi-level cell (MLC), or a triple levelcell (TLC). In an embodiment, some of the memory blocks BLK1 to BLKz maybe SLC blocks, and the other memory blocks may be MLC blocks or TLCblocks.

The page buffer unit 120 may include a plurality of page buffers PB1 toPBm (where m is an integer greater than or equal to two). In anembodiment, each of the page buffers PB1 to PBm may be connected to onebit line. In an embodiment, each of the page buffers PB1 to PBm may beconnected to one bit line group, and a plurality of bit lines includedin one bit line group may share one page buffer. For example, four bitlines may configure one bit line group and may share one page buffer.The counter 130 may count the number of undererased cells to generate acount result CR, based on a page buffer signal PBS. In this case,threshold voltages of the undererased cells may be higher than an erasedetect voltage. The P/F checking unit 140 may determine whether aprogram operation is passed on memory cells, based on the count resultCR, thereby generating a pass signal or a fail signal P/F.

The control logic 150 may output various control signals for writingdata in the memory cell array 110 or reading the data from the memorycell array 110, based on a command CMD, an address ADDR, and/or acontrol signal CTRL. Therefore, the control logic 150 may overallcontrol various operations of the memory device 100. In detail, thecontrol logic 150 may provide a voltage control signal CTRL_vol to thevoltage generator 160, provide a row address X_ADDR to the row decoder170, provide a column address Y-ADDR to the page buffer unit 120, andprovide a counting control signal CTRL_cnt to the counter 130.

The voltage generator 160 may generate various kinds of voltages forperforming a program operation, a read operation, and an erase operationon the memory cell array 110, based on the voltage control signalCTRL_vol. In more detail, the voltage generator 160 may generate a wordline voltage VWL, for example, a program voltage, a read voltage, a passvoltage, an erase verify voltage, or a program verify voltage. Also, thevoltage generator 160 may further generate a string selection linevoltage and a ground selection line voltage, based on the voltagecontrol signal CTRL_vol. Also, the voltage generator 160 may furthergenerate an erase voltage which is to be supplied to the memory cellarray 110.

In response to the row address X_ADDR, the row decoder 170 may selectone memory block from among the memory blocks BLK1 to BLKz, select oneword line from among word lines WL of the selected one memory block, andselect one string selection line from among a plurality of stringselection lines SSL. The page buffer unit 120 may select some bit linesfrom among a plurality of bit lines BL in response to the column addressY-ADDR. In more detail, the page buffer unit 120 may operate as a writedriver or a sensing amplifier according to an operation mode.

FIG. 4 illustrates an equivalent circuit diagram of a first memory blockBLK1 of FIG. 3.

Referring to FIG. 4, the first memory block BLK1 may include a pluralityof NAND strings NS11 to NS33, a plurality of word lines WL1 to WL8, aplurality of bit lines BL1 to BL3, a plurality of ground selection linesGSL1 to GSL3, a plurality of string selection lines SSL1 to SSL3, and acommon source line CSL. Each (for example, NS11) of the NAND strings mayinclude a string selection transistor SST, a plurality of memory cellsMC, and a ground selection transistor GST. The string selectiontransistor SST may be connected to the string selection lines SSL1 toSSL3 corresponding thereto. Each of the plurality of memory cells MC maybe connected to the word lines WL1 to WL8 corresponding thereto. Theground selection transistor GST may be connected to the ground selectionlines GSL1 to GSL3 corresponding thereto. The string selectiontransistor SST may be connected to the bit lines BL1 to BL3corresponding thereto, and the ground selection transistor GST may beconnected to the common source line CSL.

FIG. 5 is a perspective view illustrating the first memory block BLK1 ofFIG. 3.

Referring to FIG. 5, the first memory block BLK1 may be provided in avertical direction with respect to a substrate SUB. The substrate SUBmay be of a first conductivity type (for example, a p-type), and thecommon source line CSL which extends in a first direction and is dopedwith impurities of a second conductivity type (for example, an n-type)may be provided on the substrate SUB. A plurality of insulation layersIL extending in the first direction may be sequentially provided in athird direction in a region of the substrate SUB between two adjacentcommon source lines CSL, and may be spaced apart from each other by acertain distance in the third direction.

A plurality of pillars P, which are sequentially arranged in the firstdirection and pass through the plurality of insulation layers IL in thethird direction, may be provided in a region of the substrate SUBbetween two adjacent common source lines CSL. For example, the pluralityof pillars P may contact the substrate SUB through the plurality ofinsulation layers IL. In more detail, a surface layer S of each of thepillars P may include a silicon material of a first conductivity typeand may function as a channel region. An internal layer I of each pillarP may include an air gap or an insulating material such as siliconoxide.

The insulation layers IL, the pillars P, and a charge storage layer CSprovided along an exposed surface of the substrate SUB may be providedin a region of the substrate SUB between two adjacent common sourcelines CSL. The charge storage layer CS may include a tunnelinginsulation layer, a charge trap layer, and a blocking insulation layer.Also, a gate electrode GE including the selection lines GSL and SSL andthe word lines WL1 to WL8 may be provided on an exposed surface of thecharge storage layer CS and in a region of the substrate SUB between twoadjacent common source lines CSL. A plurality of drains or draincontacts DR may be respectively provided on the plurality of pillars P.For example, the drains or drain contacts DR may include a siliconmaterial doped with impurities of the second conductivity type. The bitlines BL1 to BL3, which extend in the second direction and are spacedapart from each other by a certain distance in the first direction, maybe provided on the drains DR.

FIG. 6A illustrates a threshold voltage distribution of memory cells ofFIG. 4, and FIG. 6B illustrates a program method of forming thethreshold voltage distribution of FIG. 6A. Referring to FIG. 6A, theabscissa axis represents a threshold voltage Vth, and the ordinate axisrepresents the number of memory cells. In an embodiment, each of memorycells may be a TLC, and memory cells having an erase state may beprogrammed to have a state corresponding to one of first to seventhprogram states P1 to P7 and an erase state E. In an embodiment, each ofthe memory cells may be an MLC, and the memory cells having the erasestate may be programmed to have a state corresponding to one of thefirst to third program states P1 to P3 and the erase state E. In anembodiment, each of the memory cells may be an SLC, and the memory cellshaving the erase state may be programmed to have the erase state E orthe first program state P1.

Referring to FIG. 6B, the memory device may perform a plurality ofprogram loops PL1 to PLn (where n is an integer greater than or equal totwo) to program the memory cells in order for the memory cells to haveone of the first to seventh program states P1 to P7 and the erase stateE. Each of the program loops PL1 to PLn may include a program process ofapplying program pulses Vpgm1 to VpgmN and a verify process of applyingverify voltages Vvfy1 to Vvfy7. In a first program loop PL1, a firstprogram pulse Vpgm1 may be applied to a selected word line, andsubsequently, the verify voltages Vvfy1 to Vvfy7 may be sequentiallyapplied to the selected word line. Memory cells on which a verify passhas been performed based on the verify voltages Vvfy1 to Vvfy7 may bedetermined as having a target program state, and in a second programloop PL2, programming may be inhibited. The verify pass may denote thata memory cell is read out as an undererased cell, based on acorresponding verify voltage. In the second program loop PL2, in orderto program memory cells other than program-inhibited memory cells, asecond program pulse with a voltage Vpgm2 greater than the voltage Vpgm1of the first program pulse by an increased program voltage level ΔVpgmmay be applied, and then, a verify operation may be performedidentically to a verify process of the first program loop PL1.

FIG. 7 is a flowchart illustrating an operating method of a memorydevice according to an embodiment. Referring to FIG. 7, the operatingmethod according to an embodiment may perform an erase detect operationin performing a program operation of the memory device, and thus, maycorrespond to a method of checking a defective word line, and forexample, may include processes which are time-serially performed by thememory device 100 of FIG. 3. Description given above with reference toFIGS. 1 to 6B may be applied to the embodiment.

In operation S110, the memory device 100 may receive a program commandCMD. For example, the memory device 100 may receive the program commandCMD from the memory controller 200. Also, the memory device 100 mayfurther receive an address ADDR and data from the memory controller 200.In this manner, an erase detect operation for checking a defective wordline may be performed after the program command is received, and thememory device 100 may perform an erase verify operation in performing aprogram operation.

In operation S120, by applying an erase detect voltage to a selectedword line, the erase detect operation may be performed on memory cellsconnected to the selected word line. For example, the row decoder 170may apply the erase detect voltage to the selected word line,corresponding to the address ADDR, of the plurality of word lines WL. Inan embodiment, a voltage level of the erase detect voltage may be lowerthan a verify voltage (for example, Vvfy1 of FIG. 6A) having a lowestprogram state for memory cells. In an embodiment, the voltage level ofthe erase detect voltage may be greater than a verify voltage level (forexample, ERS_VFY of FIG. 2) having an erase state for memory cells.

In operation S130, a program voltage may be applied to the selected wordline. For example, the row decoder 170 may apply a first program pulse(for example, Vpgm1) to the selected word line, corresponding to theaddress ADDR, of the plurality of word lines WL. In operation S140, thememory device 100 may count the number of undererased cells of thememory cells on which the erase detect operation has been performed. Inan embodiment, operation S130 and operation S140 may be performedsubstantially simultaneously. However, the embodiment is not limitedthereto, and in some example embodiments, operation S140 may beperformed after operation S130. Also, in some example embodiments,operation S130 may be performed after operation S140. Hereinafter,operation S140 will be described in more detail with reference to FIG.8.

FIG. 8 illustrates a threshold voltage distribution of memory cellsbased on the operating method of FIG. 7.

Referring to FIG. 8, before a program operation, memory cells connectedto a normal word line may have a normal erase state 81, and memory cellsconnected to a defective word line may have an abnormal erase state 82.Threshold voltages of the memory cells having the abnormal erase state82 may be greater than those of the memory cells having the normal erasestate 81. In operation S120, an erase detect voltage RD_E may be appliedto a selected word line, and in operation S140, the memory device 100may count the number of undererased cells. When the erase detect voltageRD_E is applied to the memory cells having the normal erase state 81,the number of the undererased cells may be 0. When the erase detectvoltage RD_E is applied to the memory cells having the abnormal erasestate 82, the number of the undererased cells may correspond to ahatched region in the abnormal erase state 82.

Referring again to FIG. 7, in operation S150, the memory device 100 maydetermine whether the number of the undererased cells is greater than areference bit count. In detail, the reference bit count may correspondto a value where a read error (i.e., an UECC) does not occur in a readresult of each of programmed memory cells after the program operation iscontinuously performed on memory cells connected to a selected wordline. In an embodiment, the reference bit count may correspond to thenumber of bits correctable by the ECC engine 210. In an embodiment, thereference bit count may be changed. For example, when a voltage level ofthe erase detect voltage is lowered, the reference bit count mayincrease, and when the voltage level of the erase detect voltageincreases, the reference bit count may decrease. When the number of theundererased cells is determined to be greater than the reference bitcount, operation S160 may be performed, and otherwise, operation S170may be performed.

In operation S160, the program operation on the memory cells connectedto the selected word line may end. In detail, the memory device 100 mayprocess a memory block connected to the selected word line as a failblock and may transmit a fail message to the memory controller 200. Inoperation S170, the program operation on the memory cells connected tothe selected word line may be continuously performed. In detail, thememory device 100 may perform succeeding program loops.

FIG. 9 is a flowchart illustrating a program method of a memory deviceaccording to an embodiment. FIGS. 10A and 10B are timing diagramsshowing the program method of FIG. 9. Hereinafter, the program methodaccording to an embodiment will be described with reference to FIGS. 1and 9 to 10B. The program method may correspond to an implementationexample of FIG. 7, and descriptions given above with reference to FIGS.7 and 8 may be applied to the embodiment.

In operation S210, a data setup operation may be performed. For example,the memory device 100 may receive a program command CMD and program dataDATA from the memory controller 200 and may load the received programdata DATA into the page buffer unit 120. In operation S220, an erasedetect voltage RD_E may be applied to a selected word line. In operationS230, the memory device 100 may determine whether a loop count is afirst program loop PL1. When the loop count is determined to be thefirst program loop PL1, in operation S240, the memory device 100 mayapply a first program pulse Vpgm1 to the selected word line to performprogramming, and simultaneously, may count the number of undererasedcells.

In operation S250, the memory device 100 may determine whether thecounted number of the undererased cells CNTcell is greater than areference bit count REF. When the counted number of the undererasedcells CNTcell is determined to be greater than the reference bit countREF, as illustrated in FIG. 10A, the memory device 100 may end a programoperation and may process a memory block as a fail block. When thecounted number of the undererased cells CNTcell is determined to be lessthan or equal to the reference bit count REF, operation S260 may beperformed, and as illustrated in FIG. 10B, the memory device 100 maycontinuously perform the program operation.

In operation S260, the memory device 100 may determine whether a programoperation is passed on all program states. When the program operation isdetermined to be passed on all program states, the program operation mayend, and otherwise, operation S270 may be performed. In operation S270,the memory device 100 may sequentially apply a plurality of programverify voltages Vvfy to the selected word line to perform a programverify operation on each of the program states. In operation S280, theloop count may increase by one. In operation S290, for example, in asecond program loop PL2, the memory device 100 may apply a secondprogram pulse Vpgm2 to the selected word line to perform programming,and simultaneously, may perform a P/F check operation.

FIG. 11A illustrates a normal program sequence according to anembodiment.

Referring to FIG. 11A, the memory device 100 may receive a first commandCMD1, an address ADDR, data DATA including least significant bit (LSB)data, a second command CMD2, and a latch address L-ADDR indicating afirst data latch from the memory controller 200 through an I/O line IOx.In this case, the first command CMD1 may be a kind of a memoryoperation, and the second command CMD2 may represent that a data outputflow associated with the first command CMD1 is continued. The memorydevice 100 may transmit a ready/busy signal RnBx having a low level,e.g. a logic low level, to the memory controller 200, and while theready/busy signal RnBx is maintaining a low level, the memory device 100may dump the LSB data into the first data latch.

Subsequently, the memory device 100 may receive the first command CMD1,the address ADDR, data DATA including center significant bit (CSB) data,the second command CMD2, and a latch address L-ADDR indicating a seconddata latch from the memory controller 200 through the I/O line IOx. Thememory device 100 may transmit the ready/busy signal RnBx having a lowlevel to the memory controller 200, and while the ready/busy signal RnBxis maintaining a low level, the memory device 100 may dump the CSB datato the second data latch.

Subsequently, the memory device 100 may receive the first command CMD1,the address ADDR, data DATA including most significant bit (MSB) data,the second command CMD2, and a latch address L-ADDR indicating a thirddata latch from the memory controller 200 through the I/O line IOx. Thememory device 100 may transmit the ready/busy signal RnBx having a lowlevel to the memory controller 200, and while the ready/busy signal RnBxis maintaining a low level, the memory device 100 may dump the MSB datato the third data latch.

Subsequently, the memory device 100 may receive the first command CMD1,the address ADDR, and a confirm command including the second commandCMD2. In this case, the first command CMD1 may be a kind of a memoryoperation, and the second command CMD2 may indicate a program operation.The memory device 100 may transmit the ready/busy signal RnBx having alow level to the memory controller 200, and while the ready/busy signalRnBx is maintaining a low level, the memory device 100 may perform aprogram operation.

FIG. 11B illustrates an example where a defective word line is notdetected in an erase detect operation performed in a data inputinterval, according to an embodiment. Referring to FIG. 11B, a programsequence according to the embodiment corresponds to a modificationexample of FIG. 11A, and in detail, has a difference with FIG. 11A inthat the erase detect operation starts in an interval where LSB data isdumped. In the embodiment, the memory device 100 may maintain theready/busy signal RnBi at a low level from a first time t1 to a secondtime t2, dump the LSB data at the first time t1, and start the erasedetect operation on memory cells connected to a selected word line so asto check the defective word line. When the selected word line based onan address ADDR is not the defective word line as a result of the erasedetect operation, the memory device 100 may start a program operation ata third time t3.

FIG. 11C illustrates an example where a defective word line is detectedin an erase detect operation performed in a data input interval,according to an embodiment. Referring to FIG. 11C, a program sequenceaccording to the embodiment may correspond to a modification example ofFIG. 11B, and in detail, an operation after a confirm command isreceived may differ from FIG. 11B. In the embodiment, when a selectedword line based on an address ADDR is the defective word line as aresult of the erase detect operation, the memory device 100 may transmita low-level ready/busy signal RnBi representing a program fail to thememory controller 200 at a third time t3 and may end a programoperation.

FIG. 12 is a flowchart illustrating an operation between a memorycontroller and a memory device, according to an embodiment. In detail,the operation according to the embodiment may correspond to a case wherea program/erase cycle is less than or equal to a reference value. Inoperation S310, the memory controller 200 may generate a programcommand. In operation S320, the memory controller 200 may determinewhether the program/erase cycle is greater than the reference value.When the program/erase cycle is determined not to be greater than thereference value, operations S330 to S390 may be performed. For example,operations S330 to S390 may correspond to the embodiment of FIG. 11A.

In operation S330, the memory controller 200 may transmit a command CMD,an address ADDR, and LSB data to the memory device 100. For example, thecommand CMD may include the first command CMD1 and the second commandCMD2 illustrated in FIG. 11A. In operation S340, the memory device 100may dump the LSB data into a first data latch. In operation S345, thememory device 100 may transmit a ready signal to the memory controller200. For example, the ready signal may correspond to a ready/busy signalRnBx having a high level, e.g. a logic high level.

In operation S350, the memory controller 200 may transmit the commandCMD, the address ADDR, and CSB data to the memory device 100. Inoperation S360, the memory device 100 may dump the CSB data into asecond data latch. In operation S365, the memory device 100 may transmitthe ready signal to the memory controller 200. For example, when each ofmemory cells is an MLC, operations S350 to S365 may be omitted. Forexample, when each of memory cells is an SLC, operations S350 to S385may be omitted. In operation S370, the memory controller 200 maytransmit the command CMD, the address ADDR, and MSB data to the memorydevice 100. In operation S380, the memory device 100 may dump the MSBdata into a third data latch. In operation S385, the memory device 100may transmit the ready signal to the memory controller 200. In operationS390, the memory controller 200 may transmit a confirm command and theaddress ADDR to the memory device 100. In operation S395, the memorydevice 100 may perform a program operation.

FIG. 13 is a flowchart illustrating an operation between a memorycontroller and a memory device, according to an embodiment. In detail,the operation according to the embodiment may correspond to a case wherea program/erase cycle is greater than a reference value. Referring toFIG. 13, in operation S310, the memory controller 200 may generate aprogram command In operation S320, the memory controller 200 maydetermine whether the program/erase cycle is greater than the referencevalue. When the program/erase cycle is determined to be greater than thereference value, operations S410 to S490 may be performed. For example,operations S410 to S490 may correspond to the embodiments of FIGS. 11Aand 11C.

In operation S410, the memory controller 200 may transmit a command CMD,an address ADDR, and LSB data to the memory device 100. For example, thecommand CMD may include the first command CMD1 and the second commandCMD2 illustrated in FIG. 11B. In operation S420, the memory device 100may dump the LSB data into a first data latch, perform an erase detectoperation for checking a defective word line, and count the number ofundererased cells. In this case, the erase detect operation and anoperation of counting the number of the undererased cells may beperformed in a specific (or, alternatively, an arbitrary) intervalbetween operations S420 to S460. In operation S425, the memory device100 may transmit a ready signal to the memory controller 200. Forexample, the ready signal may correspond to a ready/busy signal RnBxhaving a high level. Also, the memory device 100 may continuouslymaintain a ready/busy signal RnBi at a low level so as to perform theerase detect operation.

In operation S430, the memory controller 200 may transmit the commandCMD, the address ADDR, and CSB data to the memory device 100. Inoperation S440, the memory device 100 may dump the CSB data into asecond data latch. In operation S445, the memory device 100 may transmitthe ready signal to the memory controller 200. For example, when each ofmemory cells is an MLC, operations S430 to S445 may be omitted. Forexample, when each of memory cells is an SLC, operations S430 to S470may be omitted. In operation S450, the memory controller 200 maytransmit the command CMD, the address ADDR, and MSB data to the memorydevice 100. In operation S460, the memory device 100 may dump the MSBdata into a third data latch. In operation S465, the memory device 100may transmit the ready signal to the memory controller 200. In operationS470, the memory controller 200 may transmit a confirm command and theaddress ADDR to the memory device 100.

In operation S480, the memory device 100 may determine whether thecounted number of undererased cells is greater than a reference bitcount. When the counted number of the undererased cells is determined tobe greater than the reference bit count, operation S485 may beperformed, and otherwise, operation S490 may be performed. In operationS485, the memory device 100 may transmit a fail message to the memorycontroller 200. In operation S490, the memory device 100 may perform aprogram operation.

FIG. 14 illustrates a memory device 100 a according to an embodiment.

Referring to FIG. 14, the memory device 100 a may correspond to anexample of the memory device 100 of FIG. 3. For example, a selected wordline for performing a program operation may be WL1. In a program performinterval, a program voltage may be applied to the selected word lineWL1, a ground voltage GND may be applied to a first bit line BL1, and apower supply voltage VDD may be applied to a second bit line BL2.Therefore, a first memory cell MC1 connected to the first bit line BL1may be programmed, and a second memory cell MC2 connected to the secondbit line BL2 may be program-inhibited. In this case, the first memorycell MC1 may be referred to as a programmed memory cell, and the secondmemory cell MC2 may be referred to as a program-inhibited memory cell.In a program verify interval, an erase detect voltage RD_E may beapplied to the selected word line WL1, and then, a first program verifyvoltage Vvfy1 may be applied to the selected word line WL1. Hereinafter,an operating method of the memory device 100 a will be described withreference to FIGS. 15 and 16.

FIG. 15 is a flowchart illustrating an operating method of a memorydevice according to an embodiment. Referring to FIG. 15, the operatingmethod according to an embodiment may correspond to a method whichchecks a defective word line by performing an erase detect operation ina program operation of the memory device, and for example, may includeprocesses which are time-serially performed by the memory device 100 aof FIG. 14.

In operation S510, the memory device 100 a may receive a programcommand. In operation S520, the memory device may apply the programvoltage to a selected word line. Also, the ground voltage GND may beapplied to the first bit line BL1, and the power supply voltage VDD maybe applied to the second bit line BL2. Therefore, a selected memory cellMC1 may be programmed, and an unselected memory cell MC2 may beprogram-inhibited.

In operation S530, by applying the erase detect voltage RD_E to theselected word line WL1, the memory device 100 a may perform the erasedetect operation on memory cells connected to the selected word line.For example, the memory device 100 a may apply the erase detect voltageRD_E to the selected word line WL1. In an embodiment, a voltage level ofthe erase detect voltage RD_E may be lower than a verify voltage (forexample, Vvfy1) having a lowest program state for the memory cells.

In operation S540, the memory device 100 a may count the number ofundererased cells of program-inhibited memory cells. For example, theprogram-inhibited memory cells may correspond to memory cells where atarget state is an erase state. For example, the counter 130 may receivea page buffer signal from the page buffer unit 120 and may count thenumber of undererased cells, based on the received page buffer signal.In an embodiment, the operating method may further include a process,performed between operation S540 and operation S550, of applying theprogram verify voltage to the selected word line WL1 to perform theprogram verify operation on the memory cells connected to the selectedword line WL1.

In operation S550, the memory device 100 a may determine whether thenumber of the undererased cells is greater than a reference bit count.In detail, the reference bit count may correspond to a value where aread error (i.e., an UECC) does not occur in a read result of each ofprogrammed memory cells after the program operation is continuouslyperformed on the memory cells connected to the selected word line WL1.When the number of the undererased cells is determined to be greaterthan the reference bit count, operation S560 may be performed, andotherwise, operation S570 may be performed. In operation S560, thememory device 100 a may end the program operation on the memory cellsconnected to the selected word line WL1. In detail, the memory device100 a may process a memory block connected to the selected word line WL1as a fail block. In operation S570, the program operation on the memorycells connected to the selected word line WL1 may be continuouslyperformed. In detail, the memory device 100 a may perform succeedingprogram loops.

FIG. 16 illustrates a threshold voltage distribution of memory cellsbased on the operating method of FIG. 15.

Referring to FIG. 16, before a program operation, memory cells connectedto a normal word line may have a normal erase state 161, and memorycells connected to a defective word line may have an abnormal erasestate 162. When a first program pulse Vpgm1 is applied to a selectedword line, programmed memory cells of the memory cells having the normalerase state 161 may have a first program state 164, andprogram-inhibited memory cells may maintain the normal erase state 161.When the first program pulse Vpgm1 is applied to the selected word line,programmed memory cells of the memory cells having the abnormal erasestate 162 may have a second program state 163, and the program-inhibitedmemory cells may maintain the abnormal erase state 162. When an erasedetect voltage RD_E is applied to the memory cells having the abnormalerase state 162, the number of undererased cells may correspond to ahatched region in the abnormal erase state 162.

FIG. 17 is a flowchart illustrating a program method of a memory deviceaccording to an embodiment. FIGS. 18A and 18B are timing diagramsshowing the program method of FIG. 17. Hereinafter, the program methodaccording to an embodiment will be described with reference to FIGS. 14and 17 to 18B. The program method may correspond to an implementationexample of FIG. 15, and descriptions given above with reference to FIGS.15 and 16 may be applied to the embodiment.

In operation S610, a data setup operation may be performed. In operationS620, the memory device may determine whether a loop count is a firstprogram loop PL1. When the loop count is determined to be the firstprogram loop PL1, in operation S630, the memory device may apply a firstprogram pulse Vpgm1 to a selected word line to perform programming Inoperation S640, an erase detect voltage RD_E may be applied to theselected word line. In operation S650, the memory device maysequentially apply a plurality of program verify voltages Vvfy to theselected word line to perform a program verify operation on each of theprogram states. In an embodiment, operation S650 may be performed afteroperation S640. In an embodiment, operation S640 may be performed afteroperation S650. In operation S655, the loop count may increase by one.

In operation S660, the memory device may determine whether the loopcount is a second program loop PL2. When the loop count is determined tobe the second program loop PL2, in operation S670, the memory device mayapply a second program pulse Vpgm2 to the selected word line to performprogramming, and simultaneously, may count the number of undererasedcells. In operation S675, the memory device may determine whether thecounted number of the undererased cells CNTcell is greater than areference bit count REF. When the counted number of the undererasedcells CNTcell is determined to be greater than the reference bit countREF, as illustrated in FIG. 18A, the memory device may end a programoperation and may process a memory block as a fail block. When thecounted number of the undererased cells CNTcell is determined to be lessthan or equal to the reference bit count REF, operation S680 may beperformed, and as illustrated in FIG. 18B, the memory device maycontinuously perform the program operation.

In operation S680, the memory device may determine whether a program ispassed on all program states. When the program is determined to bepassed on all program states, the program operation may end, andotherwise, operation S650 may be performed. In operation S650, thememory device may sequentially apply a plurality of program verifyvoltages Vvfy to the selected word line to perform a program verifyoperation on each of the program states. In operation S655, the loopcount may increase by one. In operation S660, the memory device maydetermine whether the loop count is the second program loop PL2. Inoperation S690, for example, in a third program loop PL3, the memorydevice may apply a third program pulse Vpgm3 to the selected word lineto perform programming, and simultaneously, may check a pass/fail of theprogram operation.

FIG. 19 is a flowchart illustrating an operating method of a memorydevice according to an embodiment. Referring to FIG. 19, the operatingmethod according to an embodiment may correspond to a method whichchecks a defective word line by performing an erase detect operation ina program operation of the memory device, and for example, may includeprocesses which are time-serially performed by the memory device 100 aof FIG. 14.

In operation S710, the memory device may receive a program command Inoperation S720, the memory device may apply a program voltage to aselected word line. For example, the memory device 100 a may apply afirst program pulse Vpgm1 to a selected word line WL1. Also, a groundvoltage GND may be applied to a first bit line BL1, and a power supplyvoltage VDD may be applied to a second bit line BL2. Therefore, aselected memory cell MC1 may be programmed, and an unselected memorycell MC2 may be program-inhibited. In operation S730, an erase detectoperation may be performed on the program-inhibited memory cells byusing a program verify voltage and a first develop time. In operationS740, a program verify operation may be performed on the programmedmemory cells by using the program verify voltage and a second developtime. In an embodiment, the first develop time may be shorter than thesecond develop time.

In operation S750, the memory device may count the number of undererasedcells of the program-inhibited memory cells. For example, theprogram-inhibited memory cells may correspond to memory cells where atarget state is an erase state. In operation S760, the memory device maydetermine whether the number of the undererased cells is greater than areference bit count. When the number of the undererased cells isdetermined to be greater than the reference bit count, operation S770may be performed, and otherwise, operation S780 may be performed. Inoperation S770, the memory device may end a program operation on thememory cells connected to the selected word line. In detail, the memorydevice may process a memory block connected to the selected word line asa fail block. In operation S780, the program operation on the memorycells connected to the selected word line may be continuously performed.In detail, the memory device may perform succeeding program loops.

FIG. 20A is a circuit diagram illustrating a page buffer PB according toan embodiment.

Referring to FIG. 20A, the page buffer PB may correspond to one of thefirst and second page buffers PB1 and PB2 of FIG. 14. The page buffer PBmay include a precharge circuit PC, a sensing latch SL, first to thirddata latches DL1 to DL3, and a cache latch CL which are connected to asensing node SO. The number of the first to third data latches DL1 toDL3 may vary based on a data bit stored in a memory cell. Also, the pagebuffer PB may further include a bit line selection transistor TR1, a bitline voltage control transistor TR2, a precharge transistor TR3, and aplurality of monitoring transistors TR4 to TR8.

In an embodiment, the page buffer PB may perform a program verifyoperation on memory cells which have been programmed in a programoperation, and may perform an erase detect operation onprogram-inhibited memory cells. In detail, the page buffer PB may storedata, sensed through a bit line BL in a program verify operation, in thesensing latch SL. In this case, a second develop time for the programmedmemory cells may be longer than a first develop time for theprogram-inhibited memory cells.

The first data latch DL1 storing target data may be set based on thesensed data stored in the sensing latch SL. For example, when the senseddata represents completion of programming, the first data latch DL1 maybe changed to a program inhibit setting for a memory cell selected froma below-described program loop. The cache latch CL may temporarily storeinput data provided from the outside. In the program operation, thetarget data stored in the cache latch CL may be stored in the first tothird data latches DL1 to DL3.

FIG. 20B is a timing diagram showing control signals applied to the pagebuffer PB of FIG. 20A.

Referring to FIGS. 20A and 20B, at a time T1, a precharge control signalLOAD may be provided at a low level (for example, 0V) so as to prechargethe sensing node SO. Therefore, the precharge transistor TR3 may beturned on, and a voltage level of the sensing node SO may increase to aprecharge level (for example, Vpre2). Also, a bit line voltage controlsignal BLSHF may be shifted to a power supply voltage level (forexample, VDD) so as to precharge a bit line BL connected to the sensingnode SO. Accordingly, the bit line voltage control transistor TR2 may beturned on, and a voltage level of the bit line BL may increase to acertain bit line voltage. A precharge operation on the bit line BL maybe performed until the precharge transistor TR3 is turned off. At thistime, a bit line clamping control signal BLCLAMP, a ground controlsignal SOGND, and a monitor control signal MON1 may be provided at a lowlevel (for example, 0V), and a bit line setup control signal BLSETUP maybe provided at a power supply voltage level (for example, VDD).

At a time T2, a develop operation on the sensing node SO may beperformed. In order to develop the sensing node SO, the prechargecontrol signal LOAD and the monitor control signal MON1 may be shiftedto the power supply voltage level (for example, VDD). Therefore, avoltage of the sensing node SO may be lowered based on a thresholdvoltage of a selected memory cell, and the voltage of the sensing nodeSO may be stored in the sensing latch SL. At a time T3, data may belatched in a data latch DL, based on data stored in the sensing latchSL.

FIG. 21 illustrates a threshold voltage distribution of memory cellsbased on the operating method of FIG. 19. Referring to FIG. 21, before aprogram operation, memory cells connected to a normal word line may havea normal erase state 211, and memory cells connected to a defective wordline may have an abnormal erase state 212. When a first program pulseVpgm1 is applied to a selected word line, programmed memory cells of thememory cells connected to the selected word line may have a firstprogram state 213, and program-inhibited memory cells may maintain thenormal erase state 211 or the abnormal erase state 212.

In an embodiment, an erase detect operation may be performed on theprogram-inhibited memory cells by using a first program verify voltageVvfy1 and a first develop time DVL1. Subsequently, the number ofundererased cells of the program-inhibited memory cells may be counted,and the undererased cells may correspond to the hatched region in theabnormal erase state 212. In an embodiment, a program verify operationmay be performed on the programmed memory cells by using the firstprogram verify voltage Vvfy1 and a second develop time DVL2.

FIG. 22 illustrates a memory device 100 b according to an embodiment.

Referring to FIG. 22, the memory device 100 b may correspond to anexample of the memory device 100 of FIG. 3. A page buffer unit 120 a mayinclude first and second page buffers 121 and 122. The first page buffer121 may include a precharge circuit 1211, a connection unit 1212, and alatch 1213. The connection unit 1212 may connect a first bit line BL1 toa first sensing node SO1. The second page buffer 122 may include aprecharge circuit 1221, a connection unit 1222, and a latch 1223. Theconnection unit 1222 may connect a second bit line BL2 to a secondsensing node SO2. For example, each of the precharge circuits 1211 and1221 may correspond to the precharge circuit PC and the third transistorTR3 of FIG. 20A, each of the connection units 1212 and 1222 maycorrespond to the first and second transistors TR1 and TR2 of FIG. 20A,and each of the latches 1213 and 1223 may correspond to the fourth toeighth second transistors TR4 to TR8, the sensing latch SL, the first tothird data latches DL1 to DL3, and the cache latch CL of FIG. 20A.Elements of the page buffer unit 120 a, for example, the prechargecircuits 1211 and 1221, the connection units 1212 and 1222, the latches1213 and 1223, and the counter 130 may be implemented in hardware.

In a program interval, a program voltage may be applied to a selectedword line WL1, a ground voltage GND may be applied to a first bit lineBL1, and a power supply voltage VDD may be applied to a second bit lineBL2. Therefore, a first memory cell MC1 connected to the first bit lineBL1 may be programmed, and a second memory cell MC2 connected to thesecond bit line BL2 may be program-inhibited. In a program verifyinterval, a first program verify voltage Vvfy1 may be applied to theselected word line WL1. In an embodiment, the first page buffer 121connected to the first memory cell MC1 may perform a program verifyoperation on the first memory cell MC1 by developing the first sensingnode SO1 during a second develop time DLV2. In an embodiment, the secondpage buffer 122 connected to the second memory cell MC2 may perform anerase detect operation on the second memory cell MC2 by developing thesecond sensing node SO2 during the second develop time DLV2.Hereinafter, an operating method of the memory device 100 b will bedescribed in detail with reference to FIGS. 23 to 25B.

FIG. 23 is a flowchart illustrating a program method of a memory deviceaccording to an embodiment. FIG. 24 is a timing diagram for describingan example of an operation of a page buffer unit of FIG. 22, based onthe program method of FIG. 23. FIGS. 25A and 25B are timing diagramsshowing the program method of FIG. 23. The operating method according toan embodiment, for example, may include processes which aretime-serially performed by the memory device 100 b of FIG. 22.Hereinafter, the program method according to an embodiment will bedescribed with reference to FIGS. 23 to 25B. The program method maycorrespond to an implementation example of FIG. 19, and descriptionsgiven above with reference to FIGS. 19 to 21 may be applied to theembodiment.

In operation S810, a data setup operation may be performed. In operationS820, the memory device may determine whether a loop count is a firstprogram loop PL1. When the loop count is determined to be the firstprogram loop PL1, in operation S830, the memory device may apply a firstprogram pulse Vpgm1 to a selected word line to perform programming. Inoperation S840, the memory device may determine whether a programoperation is passed on all program states. When the program operation isdetermined to be passed on all program states, a program operation mayend, and otherwise, operation S845 may be performed. In operation S845,the memory device may determine whether the loop count is the firstprogram loop PL1.

When the loop count is determined to be the first program loop PL1, inoperation S850, the memory device may perform a program verify operationon programmed memory cells by using a first program verify voltageVvfy1, and simultaneously, may perform an erase detect operation forprogram-inhibited memory cells. For example, a program verify intervalwhere the first program verify voltage Vvfy1 is applied to the selectedword line may correspond to a precharge interval, a develop interval,and a sensing interval. In the precharge interval, the first and secondbit lines BL1 and BL2 may be precharged with a certain bit line voltage,and the first and second sensing nodes SO1 and SO2 may be prechargedwith a precharge voltage (for example, Vpre2 of FIG. 20A).

In the develop interval, the first page buffer 121 connected to theprogrammed memory cell MC1 may differ from the second page buffer 122connected to the program-inhibited memory cell MC2. In an embodiment,the second sensing node SO2 connected to the program-inhibited memorycell MC2 may be developed during a first develop time DVL1. In anembodiment, the first sensing node SO1 connected to the programmedmemory cell MC1 may be developed during a second develop time DVL2. Inan embodiment, the second develop time DVL2 may be longer than the firstdevelop time DVL1.

First, an erase detect operation on the second sensing node SO2connected to the program-inhibited memory cell MC2 will be described.For example, if a voltage of the second sensing node SO2 corresponds toa solid-line graph 241, the voltage of the second sensing node SO2 maybe dropped to a reference voltage Vref or less during the first developtime DVL1, and thus, the program-inhibited memory cell MC2 may be sensedas an on cell. Also, if the voltage of the second sensing node SO2corresponds to a dotted-line graph 242, the voltage of the secondsensing node SO2 may not be dropped to the reference voltage Vref orless during the first develop time DVL1, and thus, the program-inhibitedmemory cell MC2 may be sensed as an undererased cell.

Next, a program verify operation on the first sensing node SO1 connectedto the programmed memory cell MC1 will be described. For example, if avoltage of the first sensing node SO1 corresponds to the solid-linegraph 241, the voltage of the first sensing node SO1 may be dropped tothe reference voltage Vref or less during the second develop time DVL2,and thus, the programmed memory cell MC1 may be sensed as an on cell.Also, if the voltage of the first sensing node SO1 corresponds to thedotted-line graph 242, the voltage of the first sensing node SO1 may bedropped to the reference voltage Vref or less during the second developtime DVL2, and thus, the programmed memory cell MC1 may be sensed as anon cell.

As described above, according to the embodiment, the second develop timeDVL2 for a program verify operation on programmed memory cells may belonger than the first develop time DVL1 for an erase detect operation onprogram-inhibited memory cells, and thus, memory cells, having athreshold voltage lower than the first program verify voltage Vvfy1, ofthe program-inhibited memory cells may be determined as undererasedcells. Accordingly, the same effect as application of an erase detectvoltage lower than the first program verify voltage Vvfy1 for the erasedetect operation is obtained.

In operation S865, a loop count may increase by one. In operation S810,whether the loop count is the first program loop PL1 may be determined,and in operation S870, whether the loop count is the second program loopPL2 may be determined. When the loop count is determined to be thesecond program loop PL2, in operation S880, programming may be performedby applying the second program pulse Vpgm2 to a selected word line, andsimultaneously, the number of undererased cells may be counted. Inoperation S885, the memory device may determine whether the countednumber of the undererased cells CNTcell is greater than a reference bitcount REF. When the counted number of the undererased cells CNTcell isdetermined to be greater than the reference bit count REF, asillustrated in FIG. 25A, the memory device may end a program operationand may process a memory block as a fail block. When the counted numberof the undererased cells CNTcell is determined to be less than or equalto the reference bit count REF, operation S840 may be performed, and asillustrated in FIG. 25B, the memory device may continuously perform theprogram operation.

In operation S840, the memory device may determine whether a programoperation is passed on all program states. When the program operation isdetermined to be passed on all program states, the program operation mayend, and otherwise, operation S845 may be performed. When the loop countis determined to be the second program loop PL2, in operation S860, thememory device may sequentially apply a plurality of program verifyvoltages Vvfy to the selected word line to perform a program verifyoperation on each of the program states. In operation S865, the loopcount may increase by one. In operation S820, whether the loop count isthe first program loop PL1 may be determined, and in operation S870,whether the loop count is the second program loop PL2 may be determined.When the loop count is determined to be the third program loop PL3, inoperation S890, the memory device may apply a third program pulse Vpgm3to the selected word line to perform programming, and simultaneously,may check a pass/fail of the program operation.

FIG. 26 is a timing diagram for describing an example of an operation ofthe page buffer unit of FIG. 22, based on the program method of FIG. 23.Hereinafter, an operation of the page buffer unit will be described withreference to FIGS. 23 and 26. In an embodiment, by using the firstprogram verify voltage Vvfy1, a program verify operation may beperformed on programmed memory cells, and simultaneously, an erasedetect operation may be performed on program-inhibited memory cells. Forexample, a program verify interval where the first program verifyvoltage Vvfy1 is applied to a selected word line may correspond to afirst precharge interval, a first develop interval, a first sensinginterval, a second precharge interval, a second develop interval, and asecond sensing interval. In the first precharge interval, the first andsecond bit lines BL1 and BL2 may be precharged with a certain bit linevoltage, and the first and second sensing nodes SO1 and SO2 may beprecharged with a precharge voltage (for example, Vpre2 of FIG. 20A).

In the first develop interval, the first and second sensing nodes SO1and SO2 may be developed during the first develop time DVL1. Forexample, data sensed through the first sensing node SO1 may be stored ina first sensing latch included in the latch 1213, and data sensedthrough the second sensing node SO2 may be stored in a first sensinglatch included in the latch 1223. In the first sensing interval, in eachof the latches 1213 and 1223, a data latch may be set based on the datastored in the first sensing latch. In the second precharge interval, thefirst and second sensing nodes SO1 and SO2 may be precharged with theprecharge voltage Vpre2.

In the second develop interval, the first and second sensing nodes SO1and SO2 may be developed during the second develop time DVL2. In thiscase, the second develop time DVL2 may be longer than the first developtime DVL1. For example, data sensed through the first sensing node SO1may be stored in a second sensing latch included in the latch 1213, anddata sensed through the second sensing node SO2 may be stored in asecond sensing latch included in the latch 1223. In this case, one of aplurality of latches may be used as the second sensing latch. In thesecond sensing interval, in each of the latches 1213 and 1223, a datalatch may be set based on the data stored in the second sensing latch.

In an embodiment, the first page buffer 121 connected to the programmedmemory cell MC1 may determine a program pass/fail, based on the datastored in the second sensing latch. In an embodiment, the second pagebuffer 122 connected to the program-inhibited memory cell MC2 mayperform the erase detect operation, based on the data stored in thefirst sensing latch. Therefore, even when the same first program verifyvoltage Vvfy1 is applied to the selected word line, a result where theprogram verify operation is performed on programmed memory cells and theerase detect operation is performed on program-inhibited memory cells isobtained.

FIG. 27 is a flowchart illustrating an operating method of a memorydevice according to an embodiment. Referring to FIG. 27, the operatingmethod according to an embodiment may correspond to a method whichchecks a defective word line by performing an erase detect operation ina program operation of the memory device, and for example, may includeprocesses which are time-serially performed by the memory device 100 aof FIG. 14. Descriptions given above with reference to FIGS. 1 to 26 maybe applied to the embodiment.

In operation S910, the memory device may receive a program command. Inoperation S920, the memory device may determine whether a program/erasecycle is greater than a reference value. When the program/erase cycle isdetermined to be greater than the reference value, operation S930 may beperformed, and otherwise, operation S970 may be performed. In operationS930, an erase detect operation may be performed before or in the middleof performing a program operation. In operation S940, the number ofundererased cells may be counted. In operation S950, the memory devicemay determine whether the number of the undererased cells is greaterthan a reference bit count. When the number of the undererased cells isdetermined to be greater than the reference bit count, operation S960may be performed, and otherwise, operation S970 may be performed.

FIG. 28 is a block diagram illustrating an example where a memory deviceaccording to embodiments is applied to an SSD system 1000. Referring toFIG. 28, the SSD system 1000 may include a host 1100 and an SSD 1200.The SSD 1200 may transmit or receive a signal to or from the host 1100through a signal connector and may be supplied with power through apower connector. The SSD 1200 may include an SSD controller 1210, anauxiliary power supply 1220, and a plurality of memory devices 1230,1240, and 1250. The memory devices 1230, 1240, and 1250 may each be avertically stacked NAND flash memory. In this case, the SSD 1200 may beimplemented by using the embodiments described above with reference toFIGS. 1 to 27.

While inventive concepts have been particularly shown and described withreference to embodiments thereof, it will be understood that variouschanges in form and details may be made therein without departing fromthe spirit and scope of the following claims.

What is claimed is:
 1. An operating method of a non-volatile memorydevice including a plurality of memory cells respectively connected to aplurality of word lines, the operating method comprising: in response toa program command, applying an erase detect voltage to a selected wordline of the plurality of word lines to perform an erase detect operationon the memory cells connected to the selected word line; after the erasedetect operation, applying a program voltage to the selected word line;and counting a number of undererased cells of the memory cells on whichthe erase detect operation has been performed.
 2. The operating methodof claim 1, further comprising, in response to the number of theundererased cells being greater than a reference bit count, ending aprogram operation triggered by the program command.
 3. The operatingmethod of claim 1, further comprising, in response to the number of theundererased cells being greater than a reference bit count, processing amemory block connected to the selected word line as a fail block.
 4. Theoperating method of claim 1, wherein a voltage level of the erase detectvoltage is less than a verify voltage level having a lowest programstate for the memory cells.
 5. The operating method of claim 1, whereina voltage level of the erase detect voltage is greater than a verifyvoltage level having an erase state for the memory cells.
 6. Theoperating method of claim 1, wherein a voltage level of the erase detectvoltage is the same as a verify voltage of a lowest program state forthe memory cells, and a develop time of a sensing node in the erasedetect operation is shorter than a develop time of a sensing node in averify operation having the lowest program state.
 7. The operatingmethod of claim 1, wherein the counting is performed substantiallysimultaneously with the applying of the program voltage.
 8. Theoperating method of claim 1, further comprising, after the applying ofthe program voltage, applying a program verify voltage to the selectedword line.
 9. The operating method of claim 1, wherein a programoperation triggered by the program command includes a plurality ofprogram loops which are sequentially performed, and each of theplurality of program loops includes a program perform interval and aprogram verify interval after the program perform interval, and thecounting is performed in a program perform interval of a first programloop of the plurality of program loops.
 10. The operating method ofclaim 1, further comprising: receiving the program command, thereceiving of the program command including receiving a first programcommand, an address, and least significant bit (LSB) data, and receivinga second program command, the address, and most significant bit (MSB)data, wherein the performing of the erase detect operation is performedafter the receiving of the first program command.
 11. An operatingmethod of a non-volatile memory device including a plurality of memorycells respectively connected to a plurality of word lines, the operatingmethod comprising: in response to a program command, applying a programvoltage to a selected word line of the plurality of word lines; afterthe applying of the program voltage, applying an erase detect voltage tothe selected word line to perform an erase detect operation onprogram-inhibited memory cells of memory cells connected to the selectedword line; and counting a number of undererased cells of theprogram-inhibited memory cells on which the erase detect operation hasbeen performed.
 12. The operating method of claim 11, furthercomprising, in response to the number of the undererased cells beinggreater than a reference bit count, ending a program operation triggeredby the program command.
 13. The operating method of claim 11, furthercomprising: after the performing of the erase detect operation, applyinga program verify voltage to the selected word line to perform a programverify operation on programmed memory cells of the memory cellsconnected to the selected word line.
 14. The operating method of claim11, further comprising: after the applying of the program voltage andbefore the performing of the erase detect operation, applying a programverify voltage to the selected word line to perform a program verifyoperation on programmed memory cells of the memory cells connected tothe selected word line.
 15. The operating method of claim 11, furthercomprising applying an additional program voltage, having a voltagelevel greater than the program voltage, to the selected word line,wherein the counting is performed substantially simultaneously with theapplying of the additional program voltage.
 16. An operating method of anon-volatile memory device including a plurality of memory cellsrespectively connected to a plurality of word lines, the operatingmethod comprising: in response to a program command, applying a programvoltage to a selected word line of the plurality of word lines; using aprogram verify voltage, performing a program verify operation onprogrammed memory cells of memory cells connected to the selected wordline; using the program verify voltage, performing an erase detectoperation on program-inhibited memory cells of the memory cellsconnected to the selected word line; and counting a number ofundererased cells of the program-inhibited memory cells on which theerase detect operation has been performed.
 17. The operating method ofclaim 16, further comprising, in response to the number of theundererased cells is greater than a reference bit count, ending aprogram operation triggered by the program command.
 18. The operatingmethod of claim 16, wherein in the erase detect operation, a developinterval for the program-inhibited memory cells corresponds to a firstdevelop time, and in the program verify operation, a develop intervalfor the programmed memory cells corresponds to a second develop time,longer than the first develop time.
 19. The operating method of claim16, wherein the program-inhibited memory cells include memory cellswhere a target state is an erase state.
 20. The operating method ofclaim 16, further comprising applying an additional program voltage,which is greater than the program voltage, to the selected word line,wherein the counting is performed substantially simultaneously with theapplying of the additional program voltage.